During the course of the combustion processes in combustion plants —depending on the type of fuel used—there are dust emissions, whereby, especially in the case of solid fuel combustion plants and the fuels burnt there, these are of significant importance. To prevent such dusts being emitted into the environment, each country has different statutory regulations, which limit the dust content of flue gases on their entry into the surrounding atmosphere. Thus, for example, in the Federal Republic of Germany the 17th Ordinance for the Implementation of the Federal Imission Control Act (17 .BlmschV) and the Technical Instructions Air Quality Control 2000 (TA Luft 2000) apply, limiting the dust content of the flue gases entering into the surrounding atmosphere to <10 mg dust per standard cubic meter of flue gas.
As in the case of combustion plants used commercially, for example, in the case of large scale boiler plants, flue gas temperatures of over 240 degrees C. are a common occurrence, the heat contained in the flue gases is used to prewarm the combustion air to be fed into the combustion plant in order to better exploit the energy of the flue gases before or upstream of the actual device for separating dust.
Nowadays electrostatic filter devices, for example, electrostatic filters or fibrous filters, are used as devices for separating dust.
In known combustion plants, flue gas air preheaters (LUVO) of very different designs are used to preheat the combustion air, for example, rotating air preheaters, air flow preheaters, plate preheaters etc. In addition to relatively large energy losses, these show drops in pressure and are, moreover, subject to high mechanical stresses.